package org.example;

import java.util.HashSet;
import java.util.Set;
import java.util.TreeSet;

public class 双色球 {
    public static void main(String[] args) {
        Set<Integer> set = new HashSet<>();
        for (int i=0; i<10; i++){
            while(true){
                Integer m = (int)(Math.random()*20+1);
                if(set.add(m)){
                    System.out.println(m);
                    break;
                }
            }
        }
        char c = 74;
        System.out.println(c);
        String s = "Example";
        int i = s.length();
        System.out.println(i);
    }
}
